Apparatus for cathode disintegration



y 1 1940- B. BERGHAUS E1 AL 2,206,020

APPARATUS FOR CATHODE DISINTEGRATION Filed March 2a. 1938 I Q 21 2:5222? E Q: 79 3a a: 3 51 &= E I@. :3 a: Q 3 @3 Z 0 a 15- w 2' E Z 1 F 25 K I 1* I E 1 T /vl 6A/?r 336! 607 20 m B ham/1% Patented July 2,1940

UNITED STATES APPARATUS FOR CATHODE DISINTEGRATION Bernhard Berghaus, Berlln-Lankwitz, and Wilhelm Burkhardt, Berlin-Grunewald, Germany; said Burkhardt assignor to said Berghaus Application March 28, 1938, Serial No. 193,557 In Germany March 25, 193'! 1 Claim. (01. 250-215 It is known in cathode disintegration to disintegrate the cathodes in a solid state, for instance, in the form of discswire or tape. Owing to the small disintegration speeds thereby ob- 5 tained cathode disintegration has hitherto received only alimited application. The present invention substantially increases the speed of dis-.

integration.

The invention relates to a method of cathode disintegration and it mainly consists in that the cathode-material is disintegrated in a liquid state. The cathode material is fused in a metallic or non-metallic crucible, which is preferably arranged on a metallic cathode carrier, The cathode carrier is surrounded at a small distance by a metallic covering which protects it and the insulation against disintegration. In order-t0 protect the outer walls of the crucible placed thereon against disintegration, the crucible is also surrounded at a short distance by a metallic covering. The distance of the screen for the cathode carrier and the crucible must be smaller than the distance of the glow fringe formed around the cathode. A distance of the order of 26 1.5 to 3 mm. has been found suitable in practical operation. This arrangement allows of a very large power being applied to the path of discharge, so that the coating material can be fused solely by the glow current. Preferably a mag- 30 netic field may be provided for the orientation of the particles disintegrated from the cathode onwards.

It is known from the literature that an increase Time of Disintegrated 45 $5 ,2 1.2 Watts amount in mg.

Solid cadmium 5 17 183 Liquid cadmium 5 154 16, 500 Solid silver: 3 38 5 2. 4 50 Liquid silver 3 160 In this comparison the surface areas of the solid and liquid material were equal. As compared with the increase in output it is found that 55 the disintegrated amount increases, not only in proportion with the output but greatly beyond it. It has been ascertained that with further increase in output, that is to say, with increased temperature of the melt, the yield is increased. The material to be disintegrated may be fused in the crucible additionally by other known heating methods, for instance, by means of resistance heating or high frequency heating etc. Additional heating is an advantage when it is desired. to fuse large amounts of cathode material at the 10 same time. However, heating by the glow current alone is the simplest method and consumes least. When the cathode material is disintegrated in a metallic crucible care must be taken that the material to be disintegrated does not form a com- 5 pound with the material of the crucible. Inter alia, cadmium, silver and copper have, for instance, been fused and disintegrated in a molybdenum or tungsten crucible. Other metals with a higher melting point, such as nickeLcobalt, 20

chromium, vanadium, platinum, titanium, rhodium etc., which form very easily an alloy with other metals, more especially with those which come into question as crucible material, are disintegrated in non-metallic crucibles, for instance, sintered alumina, beryllium oxide, magnesium oxide, aluminium oxide, zirconium oxide, etc. In that case the bottom of the crucible is provided with a hole and is placed on a tungsten rod, which efiects the contact with the melt or with the material in a solid state.

Two forms of construction according to the invention are illustrated by way of example in the drawing in which:

Figure 1 is a section through a portion of a cathode disintegrating apparatus, taken more particularly through the cathode and crucible, and

Figure 2 is a cross-section through the cathode with a special method of fixing of a non-metallic 40 crucible.

Referring to Figure 1, I is the bottom plate and 2 the side wall of the cathode disintegration vessel which is shown only in part. 22 is the hollow cathode, preferably made of crucible shape, for 5 instance a metallic crucible of molybdenum which is carried by the supporting member 6. I8 is the metal covering and I9 is the cap which is adapted to the form of the crucible. These two parts are arranged at a small distance from the supporting member 6 and from the metal crucible 22 respectively. 23 is the metal to be disintegrated which is placed in the crucible, 24 is an insulating disc,

25 and 26 are sealing rings, for instance, of lead, and 21 is an insulating ring, which is pressed on by screws 28. 29 is the leading-in pipe for compressed air cooling and 30 is the current incoming lead for the cathode, 3| is a coil for the production of a magnetic field intended to direct the particles disintegrated from the surface of the liquid metal 23. I

The construction shown in Figure 2 diflers from the one shown in Figure 1 merely in this, that a metal pin 32 is provided on the cathode support 6, which metal pin is inserted through a hole in the bottom of the non-metallic crucible 33, and supports the crucible 33 by means of a saucerlike member 34. The metal saucer 34 is arranged to lie at a distance from the surface of the cathode support 6, so that the transmission of heat to the cathode support shall be as small as possible. The covering 18 and the cap I 9 serve as an insulation in the same manner as in the arrangement first above described. 20 is an inlet pipe for the water cooling.

Disintegration crucibles according to the invention as above described may also be mounted in a large number in thebottom of a disintegrated chamber, in order to provide articles having large suriacesfsuch as, for instance, metal sheets, with a protecting or improved cover. The shape of the crucible or crucibles may be adapted to conform to the article to be covered, so that a uniiorm cover is obtained.

What we claim is:

Apparatus for cathode disintegration of oathode material in the molten state comprising, a. crucible containing said cathode material, a metallic cathode carrier supporting the crucible and metallically connected with said cathode material, a'metal covering surrounding said carrier and spaced therefrom at a distance of a few millimeters whereby the metallic cathode carrier is protected against disintegration, a metallic covering surrounding the outer wall of the crucible at a distance of a few millimeters whereby the crucible is also protected against disintegration, and a coil surrounding said cathode carrier and the crucible and its metal covering to produce a magnetic field for directing the particles disintegrated from the cathode onwards.

BERNHARD BERGHAUS. WILHELM BURKHARDT. 

